High-speed circuit interrupter



Nov. 15, 1927. 1,649,034

R. LOGSTADT HIGH SPEED CIRCUIT INTERRUPTER Filed Sept. 8, 1925 WITNESSES: INVENTOR W a f I /4 Richard Logsfac/fi Patented Nov. 15, 1927.

UNITED STATES 1,549,034 PATENT' OFFICE.

RICHARD LOGSTADT, OF dBERLIN-SCHONEBERG, GERMANY, ASSIGNOR TO WESTING- 'HOUSE ELECTRIC 8: MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

Application filed September 8, 1925, Serial No. 54,934, and in Germany November 4, 1924.

My invention relates to protective apparatus for electrical systems and particularly to high-speed circuit interrupter-s.

One object of my invention is to provide a circuit interrupter that shall be operated by centrifugal forces.

Another object of my invention is to provide a circuit interrupter that shall utilize magnetic forces for balancing centrifugal forces until the desired conditions for operation of the circuit interrupter exist, whereupon the magnetic forces are overcomeand the centrifugal forces operate to open the circuit interrupter. 1

Another object of my invention is to provide a circuit interrupter of the centrifugal type in which the centrifugal forces are always active but are restrained by magnetic forces, whereby upon the elimination of the magnetic forces, the centrifugal forces operate to open the circuit interrupter without the loss of time required to overcome the inertia of the armature, springs and the like.

A further object of my invention is to proin response to centrifugal forces as distinguished from forces dependent upon energy stored in mechanical devices such as springs, or upon electrical forces such as those required to operate a magnet.

With the continued concentration of enormous amounts of electrical energy in electrical systems, the time element in the operation of circuit interrupters and other protective devices has been given greater consideration by the electrical industries. As a result of such studies, circuit interrupters are now made that interrupt very large amperages in fractions of a second that are measured in terms of thousandths. In order to obtain operation of circuit interrupters in such extremely short periods of time, it has heretofore been necessary that the moving parts be of relatively small mass and be operated by relative large springs or continuously energized eleetro-magnets. Such speeds of operation as are required cannot be obtained when it is necessary to accelerate a large mass of material or where it is necessary to build up a magnetic field.

I propose to' secure the foregoing results by providing a circuit interrupter in which the relatively movable contact members are rotated at relatively high speed, but are previde a circuit interrupter that shall operate Figure 1 is a schematic diagram of a cirv cuit interrupter embodying my invention,

Fig. 2 is 'a sectional view of my improved circuit interrupter along the section line 2-2 of Fig. 1 and 7 Fig. 3 is an end view in elevation of the circuit interrupter.

My invention comprises in general, a motor 1, the shaft 2 of which rotates a switch 3 that is constituted'by a pair of relatively movable contact members 4: and 5 that are pivotally mounted with respect to the shaft 2 at points 6 and 7 and which are re tained in engagement with each other by an electromagnet 8 that is also rotated by the shaft 2. A

The switch structure 3 is disposed within a housing 9 that also rotates with the shaft 2.

Referring to Fig. 1, the shaft 2 terminates within the housing 9 and the contact mem here 4: and 5 are disposed about the projected axis of the shaft beyond theend thereof and are supported upon pins 6 and 7 that are connected directly to the housing 9, through armature members 10 and. 11 respectively. Accordingly the contact members 4 and 5 in circuit-closing position oe'cupy' their relative positions shown in Fig. 3.

Withinthe housing 8 there is centrally disposed a core member 12, of rectangular cross-section, that engages with faces or pole pieces 13 and 14 on the armature members 10 and 11 respectively. The armature members 10 and 11 are separated from each other at diametrically opposite positions, thereby forming air gaps 15 in order to permit relative angular movements of the armature members about their axes 6 and 7.v However, in order to keep the magnetic reluctance of the air gap 15 at a minimum, the surfaces of the armature members 10 and 11 are inclined in order to present large surface areas. 1

The core member, 12 is normally energized by a winding 16 that is connected through slip rings 17 and 18 mounted on theshaft 2 toa battery 19 or other source of electromotive force. The current traversing the winding 16 may be regulated by varying the potential of the source of eleetromotive force 19. In normal operation, the current traversing the winding 16 is held at a constant value.

The relatively movable contact members 1 and 5 are connected by conductors 21 to slip rings 22 and 23 that are also mounted on the shaft 2 and are connected to any external apparatus (not shown). The conductors 21 extend longitudinally of the winding 16 in parallel relation to the shaft 2 to points be yond the core member 12 and winding 16 where they are bent to engage the relatively movable contact members 1 and 5. Accordingly the stationary contact members 4 and 5, the conductors 21, the winding 16, the core members 12 and the housing 9 are all adapt ed to rotate about the axis of the shaft 2 when the motor 1 is energized.

Normally, the motor 1 rotates the switch 3, with the winding 16 energized with the result that the contact members 4 and 5,are in engagehnent with each other, since the ampere turns of the winding 1,6,are suificient to overcome the ampere turns of the conductors 21, and the centrifugal. forces of armature members 10 and 11 with the result that they are held in engagement with the core member 12. However, upon the occurrence of an overload condition in the circuit comprising the conductors 21 and the relative movable contact members 4 and 5, the ampere turns of that circuit become sufliciently large to neutralize the magnetic effect of the winding 16 upon the core member 12, whereupon the -magnetic attraction between the core member 12 and the pole faces'13 and 14, becomes less than the centrifugal forces stored in the armature members 10 and 11 with the result that the armature members 10 and 11 fly out wardly, carrying with them the relative movable contact members 4 and 5 and the circuit is broken. 1

Inasmuch as the armature members 10 and 11 and the relatively movable contact members 4: and 5 are at maximum speed at all times, the separation of the contact members 4 and 5 depends only upon the magnetic relation between the windings 16 and the current traversing the windings 21, since there are no springs, large masses of mate*- rial or electromagnet to be energized in order to cause the separation of the contact members. It willthus be seen that I have pr6- vided a high speed circuit interrupter that is normally rotated at a speed sufiicient to cause immediate separation of the contact members which, in turn, are held in their circuit'closing position by an electromagnet that is controlled by the-condition in the circuit to be interrupted.

members of my circuit interrupter at all times tend toseparate by reason of their inherent centrifugal forces, it is not necessary to accelerate any mass of metal or springs or to energizeany electromagnet in order to operate the circuit interrupter. IVith this combination of elements, I am able to open a circuit of large capacity in a very small period of time that may be measured in thousandths of a second.

' While I have described and illustrated but one embodiment of my invention, it will be apparent to those skilled in the art that various changes, modifications, substitutions, additions and omissions may be made in the apparatus described without departing from the spirit and scope of the invention as set forth by the appended claims.

' I claim as my invention:

1. In a switch structure, a pair of relatively movable rotatable contact members, means for holding the relatively movable contact members in a predetermined position relative to each other while under the influence of centrifugal forces incidental to their rotary movement and means for directly controlling the last named means in accordance with the current traversing the contact members.

2. In a switch structure, a pair of relatively movable rotatable contact members, means for holdin the relatively movable contact members in a predetermined position relative to each other while under the influence of the centrifugal forces incidental to their rotation and an electrical conductor for controlling the last named means.

3. In combination, a pair of relatively movable contact members, means for imparting rotary movement to the contact members, means for retaining the contact members in engagement, and electrical means for magnetically controlling the re taining means.

4. In combination, a pair of relativ'ely movable contact members, means forrotating the contact members whereby centrifugal forces bias them to circuit-opening position, electromagnetic means for retaining the contact members in engagement, and means for controlling the effectiveness of the electromagnetic means.

-5. In combination, a pair of relatively movable contact'members, means for rotating the contact members such that centrifugal forces bias them to circuit-opening position, electromagnetic holding means therefor, 'and an augzilary winding for controlling the efi'ectiveness of the electromagnetic means.

6. In combination, a pair of relativel movable contact members comprising poe pieces, meansfor rotating the contact members at such speed that centrifugal forces Inasmuch as the relative movable contact bias them to circuit-opening position, an

electromagnet comprising a core member cooperating with the pole pieces, and an energizing'winding controlling the operation of the contact members.

7. In combination, a pair of relatively movable contact members comprising pole,

pieces, means for rotating the contact memers whereby centrifugal forces bias them'to circuit-opening position, and an electromagnet comprising a core member co-operating with the pole pieces, an energizing winding and an auxiliary winding for conirolling the operation of the contact memers.

8. In combination, a. pair of relatively movable contact members comprising pole pieces, means for rotating the contact members whereby centrifugal forces bias them to circuit opening position, and an electromagnet comprising a core member co-operating with the pole pieces, an energizing winding and an auxiliary winding for neutralizing the effect of the energizing winding to permit centrifugal forces to cause the movable contact members to be thrown away from the core member, thereby interrupting the circuit. I

9. In combination, a pair of pivoted relatively movable contact members comprising pole pieces that are rotated at. such speed that centrifugal forces bias them-to circuit opening position, and .an electromagnet comprising a core member co-operating with the pole pieces, an energizing winding and an auxiliary winding for neutralizing the effect of the energizing winding, under predetermined conditions whereby centrifugal forces cause the movable contact members to be separated from the core member, and from each other thereby interrupting the circuit. 40

Intestimony whereof I afiix my signature.

RICHARD LOGSTADT. 

